diff --git a/lib/_stream_readable.js b/lib/_stream_readable.js index a8e52f5f1d6c5b..31b129facd3a38 100644 --- a/lib/_stream_readable.js +++ b/lib/_stream_readable.js @@ -270,7 +270,11 @@ function readableAddChunk(stream, chunk, encoding, addToFront, skipChunkCheck) { } } - return needMoreData(state); + // We can push more data if we are below the highWaterMark. + // Also, if we have no data yet, we can stand some more bytes. + // This is to work around cases where hwm=0, such as the repl. + return !state.ended && + (state.length < state.highWaterMark || state.length === 0); } function addChunk(stream, state, chunk, addToFront) { @@ -304,19 +308,6 @@ function chunkInvalid(state, chunk) { } -// We can push more data if we are below the highWaterMark. -// Also, if we have no data yet, we can stand some -// more bytes. This is to work around cases where hwm=0, -// such as the repl. Also, if the push() triggered a -// readable event, and the user called read(largeNumber) such that -// needReadable was set, then we ought to push more, so that another -// 'readable' event will be triggered. -function needMoreData(state) { - return !state.ended && - (state.length < state.highWaterMark || - state.length === 0); -} - Readable.prototype.isPaused = function() { return this._readableState.flowing === false; }; diff --git a/test/parallel/test-streams-highwatermark.js b/test/parallel/test-streams-highwatermark.js index 377fe08e90d3f8..4dd9694a464272 100644 --- a/test/parallel/test-streams-highwatermark.js +++ b/test/parallel/test-streams-highwatermark.js @@ -1,31 +1,58 @@ 'use strict'; const common = require('../common'); -// This test ensures that the stream implementation correctly handles values -// for highWaterMark which exceed the range of signed 32 bit integers and -// rejects invalid values. - const assert = require('assert'); const stream = require('stream'); -// This number exceeds the range of 32 bit integer arithmetic but should still -// be handled correctly. -const ovfl = Number.MAX_SAFE_INTEGER; - -const readable = stream.Readable({ highWaterMark: ovfl }); -assert.strictEqual(readable._readableState.highWaterMark, ovfl); - -const writable = stream.Writable({ highWaterMark: ovfl }); -assert.strictEqual(writable._writableState.highWaterMark, ovfl); - -for (const invalidHwm of [true, false, '5', {}, -5, NaN]) { - for (const type of [stream.Readable, stream.Writable]) { - common.expectsError(() => { - type({ highWaterMark: invalidHwm }); - }, { - type: TypeError, - code: 'ERR_INVALID_OPT_VALUE', - message: `The value "${invalidHwm}" is invalid for option "highWaterMark"` - }); +{ + // This test ensures that the stream implementation correctly handles values + // for highWaterMark which exceed the range of signed 32 bit integers and + // rejects invalid values. + + // This number exceeds the range of 32 bit integer arithmetic but should still + // be handled correctly. + const ovfl = Number.MAX_SAFE_INTEGER; + + const readable = stream.Readable({ highWaterMark: ovfl }); + assert.strictEqual(readable._readableState.highWaterMark, ovfl); + + const writable = stream.Writable({ highWaterMark: ovfl }); + assert.strictEqual(writable._writableState.highWaterMark, ovfl); + + for (const invalidHwm of [true, false, '5', {}, -5, NaN]) { + for (const type of [stream.Readable, stream.Writable]) { + common.expectsError(() => { + type({ highWaterMark: invalidHwm }); + }, { + type: TypeError, + code: 'ERR_INVALID_OPT_VALUE', + message: + `The value "${invalidHwm}" is invalid for option "highWaterMark"` + }); + } + } +} + +{ + // This test ensures that the push method's implementation + // correctly handles the edge case where the highWaterMark and + // the state.length are both zero + + const readable = stream.Readable({ highWaterMark: 0 }); + + for (let i = 0; i < 3; i++) { + const needMoreData = readable.push(); + assert.strictEqual(needMoreData, true); } } + +{ + // This test ensures that the read(n) method's implementation + // correctly handles the edge case where the highWaterMark, state.length + // and n are all zero + + const readable = stream.Readable({ highWaterMark: 0 }); + + readable._read = common.mustCall(); + readable.read(0); +}